The typical hard disk drive includes a head disk assembly (HDA) and a printed circuit board assembly (PCBA) attached to a disk drive base of the HDA. The head disk assembly includes at least one disk (such as a magnetic disk, magneto-optical disk, or optical disk), a spindle motor for rotating the disk, and a head stack assembly (HSA). The printed circuit board assembly includes a servo control system in the form of a disk controller for generating servo control signals. The head stack assembly includes at least one head, typically several, for reading and writing data from and to the disk. In an optical disk drive, the head will typically include a mirror and objective lens for reflecting and focusing a laser beam on to a surface of the disk. The head stack assembly is controllably positioned in response to the generated servo control signals from the disk controller. In so doing, the attached heads are moved relative to tracks disposed upon the disk.
The spindle motor typically includes a rotatable spindle motor hub, a magnet attached to the spindle motor hub, and a stator. Various coils of the stator are selectively energized to form an electromagnetic field that pulls/pushes on the magnet, thereby imparting a rotational motion onto the spindle motor hub. Rotation of the spindle motor hub results in rotation of the attached disks.
The head stack assembly includes an actuator assembly, at least one head gimbal assembly, and a flex circuit assembly. A conventional “rotary” or “swing-type” actuator assembly typically includes an actuator having an actuator body. The actuator body has a pivot bearing cartridge to facilitate rotational movement of the actuator assembly. One or more actuator arms extend from the actuator body. Each actuator arm supports at least one head gimbal assembly that includes a head. An actuator coil is supported by the actuator body opposite the actuator arms. The actuator coil is configured to interact with one or more magnets, typically a pair, to form a voice coil motor (VCM). The printed circuit board assembly controls current passing through the actuator coil that results in a torque being applied to the actuator.
A latching mechanism may be provided to facilitate latching of the actuator in a parked position when the heads are not being used to interact with the tracks on the disk. In the parked position, the actuator is positioned with the heads either at an outer diameter (OD) or inner diameter (ID) of the disk. A crash stop may be coupled to the disk drive base to limit rotation of the actuator in a given direction. The crash stop is configured to contact a portion of the actuator when the actuator is rotated in a given rotational direction. Another crash stop may be provided to limit actuator rotation in an opposite rotational direction. The latching mechanism may additionally function as one of the crash stops.
Moving portions of such latching mechanism may be subject to undesirable friction with other components of the disk drive. For example, a latch arm of the latching mechanism may rub against a VCM top plate and/or disk drive base when the latch arm moves between open and closed positions adjacent the actuator. As such, a topic of concern is the potential for friction between the latching mechanism and the VCM top plate or disk drive base to resist rotation of the latching mechanism. The trend toward decreasing clearance between moving portions of such latching mechanisms and other disk drive components makes such concern more difficult to address.
Accordingly, it is contemplated that there is need in the art for an improved actuator latch configuration.